The present invention relates to a new and distinct variety of New Zealand Cabbage Tree grown for use as an ornamental for container or the landscape. The new cultivar is known botanically as CORDYLINE australis×banksii and will be referred to hereinafter by the cultivar name ‘TANA’.
CORDYLINE australis is a monocotyledonous tree which is native to New Zealand. It grows to 15 meters in height, at first on a single stem, but dividing into a much-branched crown, each branch forking after producing a flowering stem. The leaves of CORDYLINE australis are sword-shaped and predominantly stiffly upright in aspect.
A lesser known species of CORDYLINE known as CORDYLINE banksii, or New Zealand Forest Cabbage Tree, is also naturalized in New Zealand. At 3 meters to 4 meters in eventual height, CORDYLINE banksii is considerably shorter than CORDYLINE australis, and the leaves of CORDYLINE banksii are lax and drooping.
CORDYLINES are widely grown as ornamental plants in New Zealand and in Europe and in the west coast of the United States. Several cultivars are in commerce and are listed as cultivars of CORDYLINE australis having been selected as seedlings grown from seed listed as CORDYLINE australis. However, the variability in plant habit and leaf characteristics suggests that much of the collected seed has resulted from the cross-pollination of CORDYLINE australis and CORDYLINE banksii, both of which flower profusely and are capable of cross-pollination.
In 1999, the inventor purchased seed listed and labeled as CORDYLINE australis purpurea which the inventor presumed had been collected from one or more dark leafed selections of CORDYLINE australis. The inventor sowed the seeds in 1999 in Ashurst, New Zealand. Approximately 300 seeds germinated and were transplanted into pots for further evaluation during 2000. The inventor, who is very familiar with the characteristics of the different species of CORDYLINE determined that a number of the seedlings were more typical of the species CORDYLINE banksii in as much as these seedlings grew as clumps of lax drooping foliage. The inventor also observed foliage colors ranging from purple to black so that the inventor was able to select one single plant, the subject of the present invention ‘TANA’ for its unique combination of glossy dark purple to black foliage and a pronounced tendency to form a tight clump. This latter characteristic suggested to the inventor that ‘TANA’ would be a superior commercial variety by being more prolific in tissue culture multiplication, which is the standard commercial manner of increasing clonal CORDYLINES. 
The inventor grew ‘TANA’ for a further six months to the stage at which it was possible for the inventor to split the initial seedling clump into six divisions, and to observe the growth of each division. By 2001 the inventor was able to determine that the characteristics of ‘TANA’ had remained fixed and stable after the initial asexual propagation by division. Two splits were transferred to a tissue culture laboratory in January 2002 in order to determine whether ‘TANA’ remained stable and true to type during successive generations of tissue culture propagation. Upon receipt and further growing of the first plants of ‘TANA’ to be grown by tissue culture, the inventor compared their appearance with the plants which had been propagated only by division, and determined that ‘TANA’ is stable and reproduces true to type by asexual reproduction by tissue culture, and is a new and distinct cultivar of CORDYLINE. 
When compared with other varieties of CORDYLINE known to the inventor, ‘TANA’ exhibits broad long lax strap-like leaves which are deep purple to black in color, and which arise from a swollen semi-underground stem. The inventor has also observed that the darkest tones are produced when ‘TANA’ is grown in full morning sun followed by part shade by mid-day. If grown in full sun throughout, the foliage of ‘TANA’ tends to be paler.
Although all plants of CORDYLINE will eventually produce a lignified stem and will eventually produce flowers, they are sold only at a juvenile stage, namely before any flowering takes place and before whilst the leaves arise from a swollen semi-underground stem. Such juvenile plants are for their attractive foliage which is both architectural and colorful when grown in containers or when incorporated in mixed plantings in containers. ‘TANA’ has produced no flowers to date.